Method of converting alpha angelica lactone into beta angelica lactone



United States Patent Patented .Sept. 4, 1956 tars. The contact time can vary between 0.4 and 16 seconds and is preferably between 0.5 and 1.5 seconds. Depths of the bed of contact material can be varied de pending upon the Velocity rate of flow of the alpha angelica LACTONE INTO BETA ANGELICA LACTONE lactone to give contact times within the limits stated, but depths of 1 to 6 ft. are usually sufficient. g h gf zg z gz ggffiz'agigg es g; 3mg: Wh1le the pressure can be varied considerably, betware ter convers1on of the alphalnto beta-angehca lactone 1s obtained from the use of sub-atmospheric pressures. If No Drawing. Application May, 1953, atmospheric or super-atmospheric pressures are used,

serlal 355,172 there is a greater tendency to form undesirable by-prod- 5 Claims. (CL nets of a tarry nature, referred to collectively in the table given below as residual tar. Where lower pressures are used, as for instance in the neighborhood of 25 mm. Hg This invention relate to a method of converting alpha l5 pressure, the percentage of residual tar is comparatively angelica lactone into beta angelica lactone, and more parlow. Preferably, therefore, the alpha angelica lactone ticularly to such conversion by the use of clays and the vapors are passed through a bed of the activated earth like. under a pressure of between 10 and 30 mm. Hg pres- Inaccordance with my present invention, alpha angelica sure. If these relatively low pressures are employed, lactone in vapor form is passed into contact with a natthe rate of flow of the vapors through the bed becomes ural decolorizing clay, an activated clay or other suitable rather rapid, so that a deeper bed is indicated than with earth or clay under such pressure and temperature conslower rates of flow so as to obtain the length of conditions as to be converted into beta angelica lactone. tact time with the activated earth that is required for It is therefore an important object of this invention to good conversion. provide a novel and improved method of converting alpha The following example will serve to illustrate a preangelica lactone into beta angelica lactone. ferred embodiment of my invention. Other and further important objects of my invention EXAMPLE will become apparent from the following description and appended claims, The activated earth used was a natural decolorizing In carrying out the method of my invention, the vapors clay, a fullers earth, designated as FlOIeX- 163 grams of alpha angelica lactone are led into contact with a of y, calcined, granular Flore? of 4 t0 8 mesh Size natural or an activated clay. The clay can be a bentonite Was formed into a StationaIY in height Thmugh type of clay that has been acid-activated and dri d or this bed were passed vapors of alpha angelica lactone gencalcined to increase its activity. In general, however, erated in n evaporator initially charged with 1000 grams natural decolorizing earths and clays, including high magof the lactone, having an index of refraction, R. I. at 25 nesia type clays, fullers earth and the like, have been 0f l- T pors Were Pass d thr ugh the found suitable. All of these are herein generically rebed Under a Vacuurn of 25 Hg Pressure 3 Period ferred to as decolorizing clay, since all have that comf 6.7 hours. During that period, a total of 754 grams men characteristic, or property. of alpha lactone had been passed through the system The decolorizing clay is of any suitable mesh, viz. beand condensed. The refractive index of the recovered tween 1 and 16, or it may be finer or coarser, but a bed condensate at 25 C. was 1.4494. Upon vacuum fracof any finer mesh particle size tends to build up undue tional distillation under 25 mm. Hg pressure, a beta back pressure to the passage of the vapors through it, angelica lactone cut of 374 grams was obtained, repand with a coarser particle size, there may not be enough resenting a yield of 83% of the theoretical based upon contact between vapor and earth to give high yields. the alpha angelica lactone started with less that which The decolorizing clay can be in granular, extruded or Was recovered. The beta angelica lactone so produced pelletized form, but in any case is preferably of a mesh had a boiling point of 104 C. at 25 mm. Hg absolute and size between about 4 and 8. The depth of the bed can a refractive index of 1.4530 at 25 C. This represented be varied considerably, but should be relatively deep to a purity of at least 90%. insure a long contact time. The following table gives data with respect to a num- The decolorizing clay is preferably heated to a tember of runs similar to that of the foregoing example but perature between 200 and 300 C., although temperawith varying temperatures and pressures of vapor passtures as low as 150 and as high as 355 C. can be used ing through the decolorizing clay.

Earth Products Conver- YieldB Pressure, Contact sion to B, on theory, Size, Temp., mm. Hg time, sec. Alpha Beta Residual Loss, Percent Percent Source Form mesh '0. lactone, lactone, tar, Percent Percent Percent Percent Super Filtrol Pe1lets 4-8 250 760 68.8 10.8 14.7 6.2 13 34 Florex Granules. 8-10 248 760 7.4 24.9 24.9 35.6 14.6 58 33 4-8 255 760 8. 6 27. 6 29. 3 24. 0 19. 1 41 4-8 247 760 16. 0 16. 5 26.6 36. 3 2o. 3 32 4-8 251 222 7. 9 43. 0 35. 5 13. 4 8. 1 47 62 4-8 254 29 1. o 57. 1 34. 2 4. 9 3.8 45 4-8 205 25 0.86 65. 5 29. 2 a. 6 1. 7 a4 4-8 355 26 1. 05 50. 1 38.3 5. 0 6. 6 51 77 4-8 301 25 1. 0s 55. 0 a7. 4 4. 2 3. 4 51 83 Super Filtrol is an acid activated bentonite type of clay. Florex is a natural fullers earth.

with fair results. The time of contact will depend somewhat upon the temperature, the higher the temperature In figuring the yield of beta angelica lactone (B in the above table), the percentage of beta lactone recovthe shorter the time of contact to avoid formation of 75 ered is divided by the percentage of alpha lactone not the top line of the table; the equation is:

('l0068.3) It will be observed that with pressures around 25 to 30 mm. "Hg, the best yields were obtained of beta angelica lactone, while much poorer yields were obtained at atmospheric pressure (760 mm). The temperature appeared to have less effect on the yields than the pressures.

I claim as my invention:

1. The"method of converting alpha angelica lactone into beta angelicalactone, which comprises passing the vapors of alpha angelica lactone into contact with a decolorizing clay while maintaining said vapors at a temperature of between 150 and 355 C. at a pressure of between and 30 mm. Hg.

I 2. The method of converting alpha angelica lactone into beta angelica lactone, which comprises passing alpha lactone vapors at a pressure of 10 to 30 mm. Hg through a porous bed of fullers earth at a temperature of between 150 and 355 C.

3. The method of converting alpha angelica lactone into beta angelica lactone, which comprises passing alpha lactone vapors at a pressure of 10 to 760 mm. Hg through a porous bed of fullers earth at a temperature of between and 355 C.

4. The method of convertingalpha angelica lactone into betaangelica lactone, which comprises contacting vapors of'alpha'angelicalactone'with a decolorizing clay at a temperature ofbe'tween 200 and 300 C. andfor periods of time varying between 0.5 and L5 seconds and under pressures between 10 and 30 mm. Hg pressure.

5. The method of converting alpha angelica lactone into beta angelicalactone,v which comprises contacting vapors of alpha angelicalactone at a temperature of between 200 and 300 C. with a decolorizing clay of a particle size between'4 and 8 mesh for'periods of time varying betweeen 0.5 and 1.5 seconds and under pressures between 10 and 30 mm. Hg pressure. p

References Cited in'the file of this patent Wain: Annalen 229, pp. 254-257 (1885). Thiele et al.: Annalen, vol. 319, pp. 180-196 (1901). 

1. THE METHOD OF CONVERTING ALPHA ANGELICA LACTONE INTO BETA ANGELICA BACTONE, WHICH COMPRISES PASSING THE VAPORS OF ALPHA ANGELICA LACTONE INTO CONTACT WITH A DECOLORIZING CLAY WHILE MAINTAINING SAID VAPORS AT A TEMPERATURE OF BETWEEN 150 AND 355*C. AT A PRESSURE OF BETWEEN 10 AND 30 MM. HG. 